Conventionally, when biopsies were desired to be taken of the lymph nodes, for example, to aid in the diagnosis of carcinoma, the prior techniques would typically utilize a substantially rigid needle and penetrate the body via percutaneous entry. For example, U.S. Pat. Nos. 3,630,192 and 3,628,524 each to Jamshidi disclose biopsy needles suitable for percutaneous entry. More recently, less invasive flexible biopsy instruments which do not require percutaneous entry have been described. U.S. Pat. No. 4,249,541 to Pratt discloses that a flexible biopsy instrument can be utilized in combination with a fiberoptic bronchoscope.
U.S. Pat. No. 4,617,940 to Wang, the entirety of which is incorporated herein by reference, describes a completely flexible bronchoscopic needle assembly wherein relatively non-invasive biopsy procedures can be performed utilizing the needle in combination with a fiberoptic bronchoscope. The attending physician inserts the bronchoscope into a predetermined one of the patient's natural orifices depending upon the particular organ desired to be biopsied. The needle assembly, which includes an outer catheter and an inner coaxial stylus attached to a retractable needle, is slideably inserted into a receiving passageway of the bronchoscope. The needle is urged into the tissue of the patient by a stabbing force exerted on the proximal end of the stylus (e.g. the end on the exterior of the patient's body) after the outer catheter comes into the bronchoscope's field of view. The bronchoscope enables the attending physician to accurately position the needle and to penetrate the exact location of the desired organ due to the viewing capabilities provided thereby.
A particular problem in utilizing a flexible bronchoscopic needle is that the needle assembly must be flexible enough to allow the physician to maneuver the assembly through the patient's orifice to the target site, but rigid enough to allow penetration of the collection device, such as a needle, into the target tissue. The bronchial wall or hard tumor tissue will need to be penetrated and thus may present significant resistance to entry of the needle. Upon arrival at the target site, the needle assembly, particularly the distal portion of the needle assembly, should be rigid enough to provide a countering pressure against the resistance provided by the bronchial wall or hard tumor tissue or both together. Conventional needle assemblies have not provided a satisfactory means for balancing the necessary flexibility with the desired rigidity as the needle is extended into the target tissue. Thus, a need exists for a needle assembly having flexible characteristics as the assembly is maneuvered through a patient's orifice while having rigid characteristics as the needle is inserted into the target tissue.
When obtaining a biopsy of a patient's tissue, it is often desirable for the brochoscopic needle to penetrate the target site in a perpendicular direction to minimize the length of the penetration into the patents' tissue, and to reduce patient healing time. Another problem with conventional bronchoscopic needles is that the length of the needle may hinder the ability of the needle to enter a target site in a direction perpendicular to the target site wall because the length of conventional needles limits the flexibility of the distal end of conventional flexible bronchoscopic needle assemblies. Thus, a need also exists for a needle assembly having the ability to appropriately penetrate a target site wall in a direction substantially perpendicular to the target site wall.